The purpose of the proposed research is to study the critical pathway for heterosexual transmission of HIV within serodiscordant intimate relationships. The proposed research will expand on the AIDS Risk Reduction Model (ARRM), which focuses on the person's self protection motivation in the labeling of risk behaviors as problematic, the person's intention to reduce risk, and the enactment of risk reduction behaviors. The expansion will include the person's motivation to protect the partner and the motivation to preserve the relationship. Participants in the primary sample will include 200 dyads, consisting of 200 HIV positive (HIV+) persons and their heterosexual HIV negative (HIV-) partners. Study participants will be recruited from HIV care sites and from HIV testing sites. Regression analyses will provide a formal test of the three forms of the ARRM separately and then will test a combined model. A second element in the proposed study is to test the feasibility of recruiting multiple partner HIV gatekeepers (HIV- persons who have both HIV+ and HIV- sex partners). HIV gatekeepers are the critical route by which HIV can be transmitted into the general uninfected population. The project will recruit 35 gatekeeper triads (gatekeeper/HIV+/HIV-) to develop procedures for studying this complete critical pathway by which HIV will enter into the general population. This study seeks to identify the motivations, perceptions, and attitudes of both partners in critical HIV discordant relationships. Plausible interventions to reduce sexual risk need to tap into both self-interested and partner-oriented motivations. The proposed study is a necessary prelude to improving such interventions. The purpose of the proposed research is to study the critical pathway for heterosexual transmission of HIV from HIV positive persons to their HIV negative sexual partners and thus to other HIV negative persons in the general population.